Higher Incidence of BK Virus Nephropathy in Pediatric Kidney Allograft Recipients with Alport Syndrome.

A retrospective review was performed to assess the risk factors and outcomes of BK virus infection and nephropathy (BKVN), an early complication in pediatric kidney allograft recipients. The study investigated the incidence, risk factors, and clinical outcomes of BK viremia and BKVN in a Korean population of pediatric patients who received renal transplantation from 2001-2015 at the Seoul National University Hospital. BKVN was defined as biopsy-proven BKVN or plasma BK viral loads >10,000 copies/mL for >3 weeks. BK viremia was defined as a BK viral load >100 copies/mL in blood. Among 168 patients assessed for BK virus status, 30 patients (17.9%) tested positive for BK viremia at a median of 12.6 months after transplantation. BKVN was diagnosed in six patients (3.6%) at a median of 13.4 months after transplantation. Three of the six BKVN patients had Alport syndrome (p = 0.003), despite this disease comprising only 6% of the study population. Every patient with BK viremia and Alport syndrome developed BKVN, while only 11.1% of patients with BK viremia progressed to BKVN in the absence of Alport syndrome. Multivariate analysis revealed that Alport syndrome was associated with BKVN development (hazard ratio 13.2, p = 0.002). BKVN treatment included the reduction of immunosuppression, leflunomide, and intravenous immunoglobulin. No allografts were lost in the two years following the diagnosis of BKVN. In summary, the incidence of BKVN in pediatric kidney allograft recipients was similar to findings in previous reports, but was higher in patients with underlying Alport syndrome.